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BPA300 mono block

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I confirm 8 pcbs.

HIPCHECK - Thanks for donating the resistors.

Panasonic FC series cap is great for power supply. Has anyone looked into Blackgate N 10uf caps? To me, it sounded more refined than Solen but am not sure how much discount can the groupbuy bring down.

If anyone interested in the Case from My3C.net, the cost is approx. US$100/EA + shipping (approx. $35 to US but need an actual shipping quote from them for multiple pieces order.) I can call them to see if there's any discount can be given as a groupbuy if we can confirm the # of cases needed.

I have a Rowland Synergy/Coherence II input stage schematic I got from an Italy audio magazine review. I am sure the input stage can be back engineered easily if anyone's interested. The new Rowland amps use Lundahl LL1545A which is much cheaper than Jensen and provides fully balanced outputs; but the topology is similar.
 
analogdiy said:

I have a Rowland Synergy/Coherence II input stage schematic I got from an Italy audio magazine review. I am sure the input stage can be back engineered easily if anyone's interested. The new Rowland amps use Lundahl LL1545A which is much cheaper than Jensen and provides fully balanced outputs; but the topology is similar.
I would like to see it, please.

:cool:
 
Does anyone have experience with these transformers? Comparisons to Jensen version? i.e. does it actually make a difference that it is "fully balanced" or not? It is a nice-ety but maybe not a requirement since the line level signals are usually somewhat shielded inside the case.
 
alexw88 said:


The DRV134's DC offset can be as high as 20mV, so I have to use the input cap to block the DC.

An alternate solution would be the Jeff Rowland way - to use a input transformer to split the input signal to normal phase and reversed phase. The advantage is that you can save the DRV134 and related circuit. Also the transformer can block all the DC


Better don´t do that. DC saturated transformer is not something you want.

Transformer (good one) is far better and more elegant way to change signal from unbalanced to balanced and vice versa, plus you can do some signal voltage correction with transformer winding ratios, plus you have fully galvanic separation (floating) of components.
 
analogdiy said:

I have a Rowland Synergy/Coherence II input stage schematic I got from an Italy audio magazine review. I am sure the input stage can be back engineered easily if anyone's interested. The new Rowland amps use Lundahl LL1545A which is much cheaper than Jensen and provides fully balanced outputs; but the topology is similar.


This method
 
I'm using two of these per mono. I think they are more than adequate (6.5"x4.75"x2.75"). Cheap too.

433f_1.jpg


http://cgi.ebay.com/Large-Aluminum-...ryZ92078QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
 
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